In a multihop communication system, a relay communication apparatus (hereinafter also referred to simply as a communication apparatus) is connected in multiple stages between a terminal transmitting data and a terminal receiving the data and the data is transmitted via the communication apparatus. The communication apparatus has a wireless communication interface or a wired communication interface and transfers data wirelessly or via a wire. Thus, the multihop communication system is seen as promising as a technique to reduce communication wiring costs with the use of wireless communication in industrial fields such as production control systems.
According to the multihop communication system described in Patent Document 1, selecting plural communication paths having least radio frequency interference to a terminal of a data destination is disclosed. A communication apparatus constituting a communication path transmits and receives information about network topology and information of intensity of received radio waves to and from other communication apparatuses, and plural communication paths having little radio frequency interference are decided. The effect and advantage thereof is to increase communication throughput and reduce deterioration in network quality.
According to the multihop communication system described in Patent Document 2, constructing communication paths to a terminal of a data destination in the form of main and sub communication paths and switching to the sub communication path when a communication failure occurs in the main communication path is disclosed. Then, after the occurrence of the communication failure in the main communication path, data to be transmitted to the destination is resent using the sub communication path. The effect and advantage thereof is to prevent data from becoming missing, that is, improve data arrival rate.